Search and rescue efforts for missing Titan sub: All we know

The race against time to find a submersible that disappeared on its way to the Titanic wreckage site entered a new phase of desperation on Thursday morning as the final hours of oxygen possibly left on board the tiny vessel ticked off the clock. The vessel, named Titan, lost communication with tour operators on Sunday while about 700km (435 miles) south of St John's, Newfoundland, during a voyage to the Titanic shipwreck off the coast of Canada. The 6.7-metre-long OceanGate Expeditions vessel began its descent at 8am (12:00 GMT) on Sunday. Considering that it had a 96-hour air supply from the time it is sealed, according to its specifications, the US Coast Guard estimated oxygen in the submersible would have run out at about 10:00 GMT on Thursday. This can vary depending on a few factors, such as whether the sub still has power in the icy depths.